### Publications

Solving problems by looking at a discriminant. Mathematical Reflections (2020), no. 4, pp. 1-10.
With M. Z. Garaev & C. A. Díaz: Product of subsets of small intervals and points on exponential curves modulo a prime. Acta Arith. 193 (2020), no. 3, pp. 309-319.
The group-theoretic analog of Kuratowski's closure-complement theorem. Amer. Math. Monthly 126 (June-July 2019), no. 6, pp. 519-526, MR3956309.
With M. Z. Garaev: A note on $n!$ modulo $p$. Monatsh. Math. 182 (January 2017), no. 1, pp. 23-31, MR3592116.
With M.-C. Chang, J. Cilleruelo, M. Z. Garaev, I. E. Shparlinski, & A. Zumalacárregui: Points on curves in small boxes and applications. Michigan Math. J. 63 (2014), no. 3, pp. 503-534, MR3255689.
Sobre las series de los recíprocos de los números poligonales. Misc. Matemática (Octubre de 2012), núm. 55, págs. 1-11, MR3100379.

• With Daniel López-Aguayo & Leonardo Martínez-Sandoval: Un baúl de problemas olvidado (published electronically in universo.math): parte I, parte II, parte III, parte IV, parte V, parte VI

### Preprints

• On prime numbers represented by forms with a discriminant whose class number is one.

### Varia invención

— Some manuscripts:
Solutions to problems in Mathematical Reflections.

Mehr Lösungen.

— My sequences in the OEIS: A269665, A270441, A273217, A295866, A295868, A299028, A299030

— Answers to Prof. David E. Rowe's quiz on Gauss and Gaussian legends: they appeared in the pages of The Mathematical Intelligencer in 2016. Prof. Rowe was very kind to mention the answers that I sent to him in May 2016.

— On May 20 (2013), I sent a message to the editor of the Amer. Math. Monthly: it made it to the Editor's Endnotes of that year.

— A letter to the editor of Mathematical Reflections.

### Favorite sites

mathoverflow

Apuntes Misceláneos (my blog)   • Collected papers of Paul Erdös   • El i$\pi$acional   • fmat.cl

• Finding the class number of a neg. disc.   • Kuratowski's Closure-Complement Cornucopia

• Number Theory Web   • NU Problem-Solving Group   • Ponder This!